I've seen the explanations before, but I can't find them.
Particularly:
*distance from swing arm pivot shaft to shock/height adj rod and wheel axle
*one turn of the height adj rod (1.5mm?) lifts the rear how much, and where that difference is measured
*rocker arm geometry showing the significance of the difference (?) between rod and shock mounts
Plus any other knowledge you think would be worth sharing.
(I'll pay you in DIMBY bonus points)
Thanks [bow_down]
http://ducatimonsterforum.org/index.php?topic=13421.0 (http://ducatimonsterforum.org/index.php?topic=13421.0) that one?
It probably was, but I can't be sure without the pictures.
Any way - it answers most of my questions.
Thanks He Man [thumbsup]
The SSS (and ST-style DSS) suspension linkage is progressive.
At full extension, the leverage ratio is about 3:1, so for every 3mm the wheel moves, the shock moves 1mm.
IIRC, the heim joints are 1.5mm pitch, and there's two, so each turn of the pushrod makes it 3mm longer.
So that would raise the rear about 9mm.
Perhaps they're 1.25mm pitch, if so, that would raise the rear 7.5mm for one turn.
Quote from: Speeddog on July 10, 2010, 03:05:05 PM
The SSS (and ST-style DSS) suspension linkage is progressive.
At full extension, the leverage ratio is about 3:1, so for every 3mm the wheel moves, the shock moves 1mm.
IIRC, the heim joints are 1.5mm pitch, and there's two, so each turn of the pushrod makes it 3mm longer.
So that would raise the rear about 9mm.
Perhaps they're 1.25mm pitch, if so, that would raise the rear 7.5mm for one turn.
How? Because of the rocker arm geometry?
I think the rod pitch is 1.5, but doesn't the rocker arm geometry change the ride height from "your" 9mm to something less? According to Capo, about 6mm....
Yes, due to the rocker geometry.
I've taken accurate measurements of wheel travel vs. shock travel.
I don't have the info handy right now...
Older hoop style is progressive too, I've just never had the opportunity to measure one.
Quote from: Speeddog on July 11, 2010, 09:41:16 AM
Yes, due to the rocker geometry.
I've taken accurate measurements of wheel travel vs. shock travel.
I don't have the info handy right now...
Older hoop style is progressive too, I've just never had the opportunity to measure one.
If you can dig them up later - would be great [bow_down]
Swing arm pivot shaft at 0mm
Height rod/shock mount at 100mm
Rear wheel axle at 530mmIf my math isn't all wrong, this means a 1:5 ratio......
, but I wonder if x distance of rod adjustment actually lifts x mm
or if the "progressiveness" alters these numbers.
BTW Ride height adjustments are measured by the axle?
Swingarm pushes on the shock from the bottom, and the rocker arm pushes on the shock from the top.
In a simple analysis, it'd be (530/100)/2 = 2.65
But all of the angles between the parts are not 90 degrees, so it's not that simple.
I did *somewhat* accurate measurements of the effective ratio on my M695 and recorded 2.7:1 - 2.8:1 in my range of interest.
The geek in me is tempted by this package for a winter project:
http://www.tonyfoale.com/suskin/MC_setup.htm (http://www.tonyfoale.com/suskin/MC_setup.htm)
BK